Three different phosphatases have been purified from smooth muscle. Phosphatases I and II dephosphorylates myosin light chain and myosin kinase but not intact myosin. Phosphatase III dephosphorylates both myosin light chain and intact myosin at comparable rates which are higher than that for myosin kinase. The catalytic subunit of phosphatase I dephosphorylates intact myosin.